From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7A554C742B9 for ; Fri, 12 Jul 2019 11:45:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4C84C2083B for ; Fri, 12 Jul 2019 11:45:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="THypPdhe" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726700AbfGLLpK (ORCPT ); Fri, 12 Jul 2019 07:45:10 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:55464 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726250AbfGLLpK (ORCPT ); Fri, 12 Jul 2019 07:45:10 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=7WheT2sFPbpAYUphDY20RcxiluEPP2yGBWlv6nqCcpo=; b=THypPdhej8/b1YWUg1gyexApx 27rbpPcSBzGOOshG/kAYscKus1Ew/eOU5gf9H9brrUNp/PL/1yAXw/FRqTM9KeGIFKW0sT6VvmMfK dxA2HakjTPM7ZH5hjJb9dFsW475nPrHOSuB4zbm2t4DTMfP0ymwVL8uXw/pmmGlO/LSMZiZrYLz+E Uhd/JjQBAgym+6ZFFGwIegs47sVyGzYM7riZt8FU2L+e5mHTfJxzE1sYtiCrqPj9r9w/Hg2Z6pbks RYpGUb6epfiraNJqrQNpNOUonB1BaYJTo9nW9B3w6Bfs1yQ5z+bsLC0Td5ReYT0TnhNrB6jvGZx3z OGOpmAd7Q==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1hltz2-0005PZ-N5; Fri, 12 Jul 2019 11:45:00 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id C66F4209772E7; Fri, 12 Jul 2019 13:44:58 +0200 (CEST) Date: Fri, 12 Jul 2019 13:44:58 +0200 From: Peter Zijlstra To: Alexandre Chartre Cc: pbonzini@redhat.com, rkrcmar@redhat.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, dave.hansen@linux.intel.com, luto@kernel.org, kvm@vger.kernel.org, x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, konrad.wilk@oracle.com, jan.setjeeilers@oracle.com, liran.alon@oracle.com, jwadams@google.com, graf@amazon.de, rppt@linux.vnet.ibm.com, Paul Turner Subject: Re: [RFC v2 00/27] Kernel Address Space Isolation Message-ID: <20190712114458.GU3402@hirez.programming.kicks-ass.net> References: <1562855138-19507-1-git-send-email-alexandre.chartre@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1562855138-19507-1-git-send-email-alexandre.chartre@oracle.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Thu, Jul 11, 2019 at 04:25:12PM +0200, Alexandre Chartre wrote: > Kernel Address Space Isolation aims to use address spaces to isolate some > parts of the kernel (for example KVM) to prevent leaking sensitive data > between hyper-threads under speculative execution attacks. You can refer > to the first version of this RFC for more context: > > https://lkml.org/lkml/2019/5/13/515 No, no, no! That is the crux of this entire series; you're not punting on explaining exactly why we want to go dig through 26 patches of gunk. You get to exactly explain what (your definition of) sensitive data is, and which speculative scenarios and how this approach mitigates them. And included in that is a high level overview of the whole thing. On the one hand you've made this implementation for KVM, while on the other hand you're saying it is generic but then fail to describe any !KVM user. AFAIK all speculative fails this is relevant to are now public, so excruciating horrible details are fine and required. AFAIK2 this is all because of MDS but it also helps with v1. AFAIK3 this wants/needs to be combined with core-scheduling to be useful, but not a single mention of that is anywhere.